Composite torque hinges

ABSTRACT

According to the invention, in order to obtain hinges which, even if small-sized, can create a great rotational torque and, moreover, permit ready alignment of details with the rotational moment of an opening/closing body, such as a lavatory seat or lid or accentuation of any part of the action thereof, there is provided a pair of composite torque hinges each consisting of; a rotating cylinder disposed to be rotatable around a fixed shaft; a cam mechanism which is provided within the rotating cylinder and on which a compression spring is caused to work so as to control the rotational torque of the rotating cylinder; and a torsion spring which is also provided within said rotating cylinder and functions in a direction to cancel the rotational torque of the rotating cylinder in a specific rotational direction.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a pair of composite torque hingesespecially suitable for use as an opening/closing device foropening/closing bodies such as seats, lids or the like of Western-styledlavatory stools.

2. Description of the Prior Art

As opening/closing devices for seats and lids of Western-styled lavatorystools, according to the prior art, what consists of a rotating shaft onwhich a cam mechanism having a compression spring is caused to act on,and what uses a torsion spring functioning in a direction to cancel therotational torque working in a specific rotational direction of arotating shaft are publicly known.

The known configuration consisting of a rotating shaft, on which a cammechanism having a compression spring is caused to act, has theadvantage that the created torque can be readily matched with therotational moment of the seat or lid, but it also has the disadvantagethat a large apparatus is needed to achieve a great rotational torque.

On the other hand, the known one which causes only a torsion spring towork on the rotation shaft, though having the advantage that a greatrotational torque can be created even by a small mechanism, involves thedisadvantage that it is difficult to match the rotational torque itcreates, because it increases or decreases linearly, with the rotationalmoment of the seat or lid, which varies in a sine curve, and thereforeto align details with the rotational moment of the seat or lid or toaccentuate any part of the action thereof.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a pair of compositetorque hinges which, even if small-sized, can create a great rotationaltorque and, moreover, permit ready alignment of details with therotational moment of an opening/closing body, such as a lavatory seat orlid or accentuation of any part of the action thereof.

In order to achieve the aforementioned object, according to theinvention, there is provided a pair of composite torque hinges eachconsisting of a bracket; a fixed shaft engaged and fixed to thisbracket; a rotating cylinder disposed to be rotatable around this fixedshaft; a cam mechanism which is provided within this rotating cylinderand on which a compression spring is caused to work so as to control therotational torque of the rotating cylinder; and a torsion spring whichis also provided within said rotating cylinder and functions in adirection to cancel the rotational torque of the rotating cylinder in aspecific rotational direction.

In this configuration, according to the invention, the cam mechanism maybe composed of a rotating cam which, letting the fixed shaft penetratethe central part thereof, is fixed to a diaphragm provided in therotating cylinder; a sliding cam which, opposite to this rotating camand letting the fixed shaft penetrate the central part thereof, canfreely slide in the axial direction of this fixed shaft; and acompression spring which presses this sliding cam toward the fixed cam.

In each of the paired composite torque hinges according to theinvention, the torsion spring may be elastically installed, wound aroundsaid fixed shaft, between a collar engaged to the fixed shaft and therotating cylinder.

According to the invention, a protruding strip to stop turning may alsobe provided on part of the outer circumference of the rotating cylinder.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating the use of a pair of composite torquehinges for opening and closing an opening/closing body such as the seat,lid or the like of a Western-styled lavatory stool.

FIG. 2 is an exploded perspective view of one of the paired compositetorque hinges illustrated in FIG. 1.

FIG. 3 is a diagram illustrating the action of a composite torque hingeA, one of the paired hinges illustrated in FIG. 1.

FIG. 4 is a diagram illustrating the action of a composite torque hingeB, one of the paired hinges illustrated in FIG. 1.

FIG. 5 shows the curves of torques generating where a pair of compositetorque hinges according to the invention are used for opening andclosing of an opening/closing body, such as the seat, lid or the like ofa Western-styled lavatory stool.

FIG. 6 is a diagram illustrating how the opening/ closing action is tobe accentuated where a pair of composite torque hinges according to theinvention are used for opening and closing an opening/closing body, suchas the seat, lid or the like of a Western-styled lavatory stool.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Whereas a preferred embodiment of the present invention, whichrepresents an application thereof to an opening/closing body, such asthe seat, lid or the like of a Western-styled lavatory stool, isdescribed below, the invention is not limited to this embodiment, but isapplicable to a wide variety of other opening/closing bodies.

In FIGS. 1 through 4, a pair of brackets 2 are fitted to the upper endof the rear part of a Western-styled lavatory stool 1 at a prescribedspacing between them, and deformed axial parts 3a provided at one endeach of fixed shafts 3 are inserted and fixed in deformed holes 2bprovided in bearing sections 2a of these brackets 2. The other parts ofthese fixed shafts 3 than the deformed axial parts 3a are housed inrotating cylinders 4, which are made freely rotatable around the fixedshafts 3 as, in each of the cylinders 4, the inlet part of the innercircumference is borne by a large diameter part 3b, disposedcontinuously from the deformed axial part 3a of the fixed shaft 3, andone end of a deformed small diameter part 3c, disposed continuously fromthe large diameter part 3b, is borne by a bearing hole 5a provided in apartition wall 5 within the rotating cylinder 4. Incidentally, betweenthe outer circumference of each large diameter part 3b and the innercircumference of each rotating cylinder 4 is provided an O ring 6,fitted into a circumferential groove 3d provided in the large diameterpart 3b. A pair of rotating cams 7 are fixed to the partition walls 5provided within the rotating cylinders 4 by fitting a plurality ofprojections 7a, protruding from one side end of each of the cams 7, intoa plurality of engaging holes 5b disposed around bearing holes 5a of thepartition wall 5, and they rotate together with the rotating cylinders 4by passing the deformed small diameter parts 3c of the fixed shafts 3through penetrating holes 7d provided in the center of the rotating cams7.

In positions opposite to cam parts 8 of these rotating cams 7 are fittedsliding cams 9, unrotatable but free to slide, allowing the deformedsmall diameter parts 3c of the fixed shafts 3 to pass deformedpenetrating holes 9a provided in the center of the sliding cams 9, andtheir cam parts 10 are opposite to and in contact with the cam parts 8of the rotating cams 7. In this way, the rotating cams 7 and the slidingcams 9 constitute cam mechanisms 15. Between each sliding cam 9 and eachlarge diameter part 3b, a compression spring 11 is elasticallyinstalled, winding around the deformed small diameter part 3c.

On the other side of the partition wall 5 than where the rotating cams 7are fitted, torsion springs 14 are housed, and they are caused to give arotational force in one direction to the rotating cylinders 4 byengaging one end of each spring 14 to a lid 12 fitted unrotatably to therotating cylinder 4 and the other end to the fixed shaft 3 by engagingit to a collar 13, which is fastened to the fixed shaft 3 with a fittingscrew 16, with the fixed shaft 3 being caused to fit into a deformedhole 13a of the collar 13.

Fitting parts 17a and 18a of a lavatory 17 and a lavatory lid 18,respectively, are fitted to the outer circumference of the rotatingcylinders 4. To a protruding strip 4a, projecting in the axial directionof the rotating cylinder 4 on the left side in FIG. 1 on its outercircumference, is engaged one of the fitting parts 18a of the lavatorylid 18, and one of the fitting parts 17a of the lavatory seat 17 isrotatably borne by the protruding strip 4a. A protruding strip 4a on theright side, similarly, rotatably bears the other of the fitting parts18a of the lavatory lid 18, and the other of the fitting parts 17a ofthe lavatory seat 17 is engaged to that protruding strip 4a.

This configuration enables, when the lid 18 is to be opened or closed,the composite torque hinge A on the left side in FIG. 1 works to controlthat opening/closing action, and when the seat 17 is to be opened orclosed, the composite torque hinge B on the right side serves to controlthat opening/closing action. In this embodiment, a major part of thefalling moment of the opening/closing body, such as a lavatory seat, lidor the like, is borne by the torsion springs 14, and the detailedalignment or accentuation of the action or the like are performed by thecam mechanisms 15.

FIG. 5 shows the curves of torques. According to this diagram, thetorque curve of the torsion springs 14 crosses the opening/closingmoment curve of the seat 17 in the 90° position of the seat 17. Thistorque curve, though always staying below the opening/closing momentcurve of the seat 17 at an opening angle less than 90°, it is above theopening/closing moment curve of the seat 17 at any opening angle greaterthan 90°.

FIG. 6 illustrates an actual example of how details are aligned or theaction is accentuated with respect to the opening/closing moment of anopening/closing body, such as a lavatory seat, lavatory lid or the likeby using the cam mechanisms 15 in which compression springs are broughtinto action. It is seen that various accentuations are possible byappropriately designing the torque of the torsion springs and the camshape of the cam mechanisms.

Thus, when the lavatory seat 17 or the lavatory lid 18 is closed, asshown in FIG. 1, convex parts 7b of the rotating cams 7 are opposite toand in contact with convex parts 9b of the sliding cams 9, resulting inthe most tightly compressed state of the compression springs 11. Thetorsion springs 14 are in a heavily wound state. When the seat 17 or thelid 18 is to be opened from this state, since the overall torque of thehinges is slightly below the opening moment of the opening/closing body,such as the lavatory seat or the like, as indicated in FIGS. 5 and 6,the user may feel some weight or resistance at the beginning of his orher opening action. However, above 20°, where the overall torque of thehinges begins to surpass the opening/closing moment of theopening/closing body, such as the lavatory seat or the like, it can beopened with only a little force and, in the opening angle range of up to90°, the convex parts 7b of the rotating cams 7 and the concave parts 9cof the sliding cams are pressed against each other at the same time,concave parts 7c of the rotating cams 7 are opposite to the convex parts9b of the sliding cams 9, letting the seat or the like be stopped in anydesired position. When the self-standing angle of 90° is just surpassed,braking by the mutual pressing of the rotating cams 7 and the slidingcams 9 begins to work, and bouncing back or bounding is absorbed at thefull-open angle of 110°.

When closing a fully open lavatory seat, lid or the like, it can againbe stopped in any desired position in the range of opening angle between90° and 20°, and as it is let go at an opening angle of 20°, the seat orthe like will begin to close slowly and naturally drop from an angle of10°.

What is claimed is:
 1. A composite torque hinge comprising:a brackethaving a bearing section, the bracket fitted to an upper end of a rearpart of a lavatory stool; a fixed shaft having a deformed axial part, alarge diameter part, a deformed small diameter part, and a collarfastened to the fixed shaft at the end opposide the deformed axial part,the fixed shaft being engaged and fixed to the bracket by the deformedaxial part inserted through a deformed hole provided in the bearingsection of the bracket; a rotating cylinder having a partition walldefining a bearing hole provided in the rotating cylinder and a lidfixedly closing one end of the rotating cylinder, the rotating cylinderfreely rotatably mounted around the fixed shaft and the large diameterpart, the deformed small diameter part being rotatably inserted throughthe bearing hole; a cam mechanism provided within the rotating cylinderfor controlling the rotational torque of the rotating cylinder, the cammechanism comprising:a rotation cam mounted on the fixed shaft, therotation cam connected to the partition wall; a sliding cam axiallyslidably mounted on the fixed shaft in opposed relation to the rotationcam; and a compression spring mounted on the fixed shaft between thelarge diameter part and the sliding cam, the compression spring pressingthe sliding cam toward the rotation cam; and a torsion spring providedwithin the rotating cylinder acting against a rotational torque of therotating cylinder mounted on the fixed shaft between the collar and thelid.
 2. A composite torque hinge according to claim 1, wherein therotating cylinder further comprises a radially protruding strip orientedparallel with a longitudinal axis of the rotating cylinder on an outercircumference thereof, the protruding strip being engaged with a fittingpart of a lavatory lid.